NFSv4: Fix a credential refcount leak in nfs41_check_delegation_stateid

It is unsafe to dereference delegation outside the rcu lock, and in
any case, the refcount is guaranteed held if cred is non-zero.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

fs/nfs/nfs4proc.c

@@ -2778,7 +2778,6 @@ static void nfs41_check_delegation_stateid(struct nfs4_state *state)
 	if (status == -NFS4ERR_EXPIRED || status == -NFS4ERR_BAD_STATEID)
 		nfs_finish_clear_delegation_stateid(state, &stateid);
 
-	if (delegation->cred)
 	put_cred(cred);
 }